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Filtering by Subject

Printed From: LogSat Software
Category: Spam Filter ISP
Forum Name: Spam Filter ISP Support
Forum Description: General support for Spam Filter ISP
Printed Date: 14 November 2018 at 3:50am

Topic: Filtering by Subject
Posted By: Guests
Subject: Filtering by Subject
Date Posted: 29 May 2003 at 11:05pm
Just wondering if there are any immediate plans to add the option to filter by the subject line of a message?

Posted By: Guests
Date Posted: 30 May 2003 at 1:41am
If you use the keyword list it will scan not only the subject line but also the rest of the email, since subject lines in spam are often misleading as to the actual content of the email.

Posted By: Desperado
Date Posted: 31 May 2003 at 2:27am

If I may cut in ... Filtering by JUST the subject would be significantly different than scanning the whole message so I feel the question was a valid one. There are senerios where filtering by JUST the subject would catch junk but if you searched the whole message, you might get a false positive.  I, too, had wondered if this may be a good addition but dropped the thought because I hardly use the keywords anyway.  Many of our customers feel we are engaging in censorship by using keyword filtering so we have to be very careful.  What I would like to figure out is if there is a way to detect the strange scrambled garbage text in the subject and what ever the "tags" are at the bottom fo many Spam messages.

I also wonder how far into the message the scan engine searches for.  Does anyone know?

Dan Seligmann

Posted By: Guests
Date Posted: 31 May 2003 at 3:08am

From the testing I have done, when using keywords the entire email is searched excluding attachments. Filtering by subject only is too easy to bypass with false or empty subject lines. This is the main problem with SPAM in the first place. From the hundreds of thousands of emails I have filtered, very few were filtered by a keyword in the subject line. The smart SPAMMERS have known for a long time that if they were to put the true topic in the subject line, most people would just trash it with out reading it. Just like junk postal mail.

Now on to "censorship" This is a touchy subject but must be addressed. Yes in a sense filtering any email could be considered censorship which is the number one argument that Pro-SPAM pundits use to justify what their right to send SPAM. Here is the problem, SPAM - Bulkemail is un-asked for in most cases and costs ISP's and email users both time and money. Due to the abuse of the openness of email standards, bulkmailers have abused it to the point where email is rapidly becoming a useless tool.

Until the next version of SPAMFilter is released that supports the web interface which will allow the email user the ability to screen the email before it is downloaded there are only a few options. What I have offered my ISP clients is if they done want filtered email then they can have it unfiltered. Very few of them want it unfiltered. Most of them are so pissed off because of the massive amount of garbage, they would rather get no email then have to delete 100's of penis enlargment offers, Viagra, teen sex, porn, mortagage ads and the many other garbage emails that they recieve.

And the idea that the government should pass a anti-spam law that would be based on an opt-out only system is a joke. It should be an opt-in system with the ability to really opt-out anytime there after. Then people would have no reason to complain about getting email advertisments since they requested it in the first place. But the chances of this happening are very slim.

As the owner of a national ISP, I see things from the view point of one who has to pay for equipment, bandwidth, and technical support. Of all the problems I have to deal with, email is by far the most costly and as most ISP's we don't charge extra for email, it is just another part of the whole service.

Posted By: Desperado
Date Posted: 31 May 2003 at 3:23am

I agree with (nearly) everything in your post but in the real world, some people do seem to want to enlarge a wide variety of body parts!  I actually had a customer complain because, in our previous spam software, we were blocking the term "anal sex".    The conversation got very weird after that!

I gotta get home.


Posted By: Guests
Date Posted: 31 May 2003 at 3:24am

Just to clarify something. Most of the SPAM that is blocked ends up being rejected for the following reasons.
1) No reverse DNS
2) Blacklisted in 2 or more RBL
3) Keywords, either in the subject of the email or in the body

Posted By: Guests
Date Posted: 31 May 2003 at 5:50am
That is why the unfiltered list is there. I have a few strange one too. But they are the minority not the majority so putting them in the unfiltered list is easier then having hundreds of users unhappy with SPAM.

Posted By: Guests
Date Posted: 02 June 2003 at 11:57am

I agree that adding a seperate subject line only filter would help filter out certain spam.

There are some mass-spam applications that generate bulk email and create a subject line that has a generic subject, a series of spaces and finally tracking text (usually garbled letters or numbers).  One way to filter against these type of spam is to filter out any subject line that has maybe seven or more spaces in a subject line.  Even if the content of the email is obscured using HTML tricks that the regular keyword filters would not be able to read, this would catch any email generated by one of these mass-email apps.

It's a good idea and is worth considering as an additional filter.

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